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Publicações

Publicações por SYSTEM

2015

Discovering MARS: A Mobility Aware Recommender System

Autores
Leal, R; Costa, PM; Galvao, T;

Publicação
2015 IEEE 18TH INTERNATIONAL CONFERENCE ON INTELLIGENT TRANSPORTATION SYSTEMS

Abstract
Recommender systems have radically changed the way people find products, services and information. They are a precious tool in e-commerce and other online services and have slowly been clawing their way into the real-world stage. Location is one of the variables that can be useful in this new situation. While this particular area has been the subject of some research, it can go even further with the exploration of mobility. In this work, we analyze the integration of mobility in a recommender system with real mobility data from a public transportation network. We developed an algorithm that incorporates location and frequency in a conventional recommender system. Our results show successful recommendations of items adapted to users' mobility patterns.

2015

Exploring ticketing approaches using mobile technologies: QR Codes, NFC and BLE

Autores
Leal, J; Couto, R; Costa, PM; Galvao, T;

Publicação
2015 IEEE 18TH INTERNATIONAL CONFERENCE ON INTELLIGENT TRANSPORTATION SYSTEMS

Abstract
There is a growing interest in integrating public transportation with the smartphone and mobile ticketing provides just that. To do so, different technologies can be used, such as Near Field Communication, Quick Response Codes and Bluetooth Low Energy. This paper explores the possibility of implementing a mobile ticketing solution, with focus on the ticket validation process, using these technologies. They are analyzed and compared at different levels and two possible approaches proposed. Both solutions are presented in terms of infrastructure and maintenance cost, as well as passenger interaction and benefit. The feasibility and performance of the technologies is analyzed and presented in the context of the proposed approaches. As a result, a mobile ticketing solution can be implemented using different technologies, and their choice depends on factors such as the available funds, the intended interaction level, performance and the size of the target audience.

2015

One hand or two hands? 2D selection tasks with the leap motion device

Autores
Seixas, MCB; Cardoso, JCS; Dias, MTG;

Publicação
ACHI 2015 - 8th International Conference on Advances in Computer-Human Interactions

Abstract
In this paper, we present the results from an experiment designed to compare two selection gestures (hand grab and screen tap) for the Leap Motion controller in 2D pointing tasks. We used the ISO 9241-9 multi-directional tapping test for comparing the devices, and we analyze the results using standard throughput and error rate measures as well as additional accuracy measures. We also present the results from the ISO 9241-9 assessment of comfort questionnaire. To complement this analysis, the computer mouse was also evaluated in order to serve as a comparison. Results indicate that the hand grab gesture performs better than the screen tap. Copyright © IARIA, 2015.

2015

Self-organising socio-technical description in service systems for supporting smart user decisions in public transport

Autores
Dragoicea, M; Falcao e Cunha, JFE; Patrascu, M;

Publicação
EXPERT SYSTEMS WITH APPLICATIONS

Abstract
This paper describes an exploration towards the transposition of service science principles into design guidelines. This aims at capturing value co-creation service interactions embedding customer experience in service design and delivery activities. The new Socio-Technical Systems Engineering (STSE) process is proposed to guide improved design, and it is exemplified with a new real time service that provides integrated information for trip planning in a city. The STSE process supports a high level visual modelling approach assisted by model execution and simulation tools. From a service engineering perspective, the outcomes of this process are artefacts that automatically support consistency among design steps and effective integration of customer experience and stakeholder requirements through iterative cycles related to service design. The application of the STSE process in the design of an exploratory case study of a real time information and travel planning service is validated through simulation using an executable representation of requirements. It can be executed over more complex transport service offerings, with different resource allocation algorithms, or different public transport planning services over a sample of real users requesting information. Results of such a simulation are beneficial for the users, for the service providers, and for the authorities managing public transport in city or metropolitan areas.

2015

A nonparametric methodology for evaluating convergence in a multi-input multi-output setting

Autores
Horta, IM; Camanho, AS;

Publicação
EUROPEAN JOURNAL OF OPERATIONAL RESEARCH

Abstract
This paper presents a novel nonparametric methodology to evaluate convergence in an industry, considering a multi-input multi-output setting for the assessment of total factor productivity. In particular, we develop two new indexes to evaluate sigma-convergence and beta-convergence that can be computed using nonparametric techniques such as Data Envelopment Analysis. The methodology developed is particularly useful to enhance productivity assessments based on the Malmquist index. The methodology is applied to a real world context, consisting of a sample of Portuguese construction companies that operated in the sector between 2008 and 2010. The empirical results show that Portuguese companies tended to converge, both in the sense of a and beta, in all construction activity segments in the aftermath of the financial crisis.

2015

Measurement of input-specific productivity growth with an application to the construction industry in Spain and Portugal

Autores
Kapelko, M; Horta, IM; Camanho, AS; Lansink, AO;

Publicação
INTERNATIONAL JOURNAL OF PRODUCTION ECONOMICS

Abstract
Decision making in companies requires an assessment of the efficiency and productivity of individual inputs to provide insights into the scope for improvement of inputs' use. This paper estimates an input-specific Luenberger productivity growth indicator that can be decomposed to identify the contributions of input-specific technological change, technical efficiency change and scale efficiency change. These components for a specific input sum up to the aggregated indicators which are then compared with the traditional Luenberger indicator. The application focuses on panel data of Spanish and Portuguese construction firms over the period 2002-2011, accounting for three inputs: materials, labor and capital. The results show that aggregated productivity change and its components computed from the input-specific productivity indicator are different from those obtained using a traditional approach. The results also indicate that productivity change is negative for labor and capital for construction firms in both Spain and Portugal, while productivity change of materials is positive for Portugal and negative for Spain. Productivity decline is worse for capital in the Spanish construction firms, and for labor in Portugal.

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